diff options
authorAl Viro <viro@zeniv.linux.org.uk>2016-04-27 01:11:55 -0400
committerSasha Levin <sasha.levin@oracle.com>2016-05-17 16:31:08 -0400
commitd6c198421db212898a96a3e34d7e526abca67a3a (patch)
parent65c2cfa5e503d8fdca05cd6b75b78e61b4415ae4 (diff)
atomic_open(): fix the handling of create_error
[ Upstream commit 10c64cea04d3c75c306b3f990586ffb343b63287 ] * if we have a hashed negative dentry and either CREAT|EXCL on r/o filesystem, or CREAT|TRUNC on r/o filesystem, or CREAT|EXCL with failing may_o_create(), we should fail with EROFS or the error may_o_create() has returned, but not ENOENT. Which is what the current code ends up returning. * if we have CREAT|TRUNC hitting a regular file on a read-only filesystem, we can't fail with EROFS here. At the very least, not until we'd done follow_managed() - we might have a writable file (or a device, for that matter) bound on top of that one. Moreover, the code downstream will see that O_TRUNC and attempt to grab the write access (*after* following possible mount), so if we really should fail with EROFS, it will happen. No need to do that inside atomic_open(). The real logics is much simpler than what the current code is trying to do - if we decided to go for simple lookup, ended up with a negative dentry *and* had create_error set, fail with create_error. No matter whether we'd got that negative dentry from lookup_real() or had found it in dcache. Cc: stable@vger.kernel.org # v3.6+ Acked-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
1 files changed, 4 insertions, 16 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 2a8ba683a888..e1976450a1e2 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2797,22 +2797,10 @@ no_open:
dentry = lookup_real(dir, dentry, nd->flags);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
- if (create_error) {
- int open_flag = op->open_flag;
- error = create_error;
- if ((open_flag & O_EXCL)) {
- if (!dentry->d_inode)
- goto out;
- } else if (!dentry->d_inode) {
- goto out;
- } else if ((open_flag & O_TRUNC) &&
- S_ISREG(dentry->d_inode->i_mode)) {
- goto out;
- }
- /* will fail later, go on to get the right error */
- }
+ }
+ if (create_error && !dentry->d_inode) {
+ error = create_error;
+ goto out;
path->dentry = dentry;